1. Field of the Invention
This invention relates to granules of a slowly dissolving, water soluble. thermoplastic matrix containing enzymes, bacteria or bacteria/enzyme combinations, and to their use in granular septic tank bioaugmentation preparations, grease trap cleaning formulations and other bioremediation agents.
2. Discussion of the Related Art
Septic tanks and other biological treatment devices and facilities stabilize influent waste by removing biochemical oxygen demand (BOD), mineralizing carbon-containing compounds, digesting organic solids, and converting other compounds to chemical forms that are less damaging to the environment. It is important that organic components that might occlude, accumulate, and coat waste treatment, waste holding and waste conveying systems be dissolved and digested in an environmentally acceptable manner. Enzymes, bacteria, and bacteria-containing enzyme rearations are widely used in septic tank treatments, bioaugmentation agents, grease trap treatments, and bioremediation for other biological waste water processes. There is also a problem of sludge accumulation in lagoons and pits designed for the digestion of human and animal waste which needs a solution. Normally the granulated bacteria and enzymes are used as components of a comprehensive or diverse formulation which contains active ingredients compounded to enhance and accelerate the digestion of waste products. Preparations of this type are known as bioaugmenitation or bioenhancement agents. The three types of biological components of a bioenhancement agent, that is enzymes, bacteria or bacteria/enzyme combinations may be used in varying concentrations depending upon the situation. For example, some geographic areas regulate products in such manner that only viable bacteria containing additives may be used; free, active enzymes must be excluded from bioaugmentation products. In other areas combination products are used. Additionally, situations that are in food processing or medical facilities may require enzyme only (bacteria-free) products for waste treatment.
Enzymatic components and bacterial components of comprehensive formulations and enzyme/bacteria culture combinations have been used extensively to provide digestive activity in such situations. For example, previous U.S. Pat. No. 5,905,037 (Cooney--Tobey of the present invention, et al.) (May 18, 1999) describes the process and composition containing a cellulase and other enzymes with bacteria which accelerate the fiber digestion and removal of solids from septic tanks and cess pools. The U.S. Pat. No. 5,905,037 discusses Cellulases, Lipases, Proteases, Amylases and the bacteria that generate such enzymes at column 4, line 62 to column 7 line 48. which discussion is hereby incorporated by reference.
In order to maintain continuous activity of supplemental bioenhancing ingredients such as the aforementioned bacteria and enzymes, conventional art teaches the continual addition either by manual or mechanical timed addition of bioaugmentation agents to a waste water treatment, holding or conveying system. Some products specify hourly, daily, or weekly additions to waste-containing containing systems. The need for this continual addition is to maintain incremental and continuous levels of activity from the enzymes, bacteria and other biologically active components so as to have more effect upon treatment efficiency. The mechanical addition is often expensive and maintenance intensive. Manual addition is traditionally unreliable.
Other related patents include:
U.S. Pat. No. 3,242,055 DeLucia (Mar. 22, 1966) discloses at column 3, lines 1-16, "As is shown in FIG. 2. the pellet 35 comprises a blend of powder or crystalline type enzyme material 35A, e.g. lipase, trypsin, amylase, pepsin or the like, and metal filings 35B that are bonded together by a suitable bonding agent, ie. animal glue, animal glue mixed with skimmed milk, casein glue, or any suitable water soluble glue or binder non-reactive to the enzymes. The pellets 35 are sized and shaped so that they can be readily passed through the soil pipes leading to tank 20. The purpose of the metal filings, e.g. iron filings, is to weight the pellets 35. Thus as pellet 35 is introduced into the tank, it will immediately sink to the bottom of the tank and come to rest in direct contact with the sludge 30 where active bacterial action is most desired. DeLucia does not address cellulases.
At column 3. lines 43-48 it is disclosed, "If desired, such enzyme pellet construction can be sold and distributed in package containing a number of pellets bonded with each of the bonding agents above described. Trhus immediate and long lasting bacterial action can be attained by depositing one or more of the differently bonded pellets into the tank."
In FIG. 1, one pellet 35 is shown in the septic tank.
The enzyme activity of DeLucia will be concentrated around the one or limited number of pellets added to the tank.
U.S. Pat. No. 5,275,943 DiTuro (Jan. 4, 1994) discloses at the abstract, "Tablets are formed that release components over time for biological degradation of organic matter such as sewage sludge, petroleum hydrocarbons, pesticides and herbicides. The tablets contain an inner-core of a dormant live microorganism, an inner-coating over the inner-core of water soluble hydroxypropyl methylcellulose or polypropylene glycol, an outer-layer over the inner coating of sodium sulfate coated sodium carbonate peroxyhdrate particles, and an outer-coating over the outer-layer of water soluble hydroxypropyl methylcellulose or polyethylene glycol. The inner core may contain a binder such as paraffin, gelatin and dextrose, and the outer-layer may contain additives such as enzymes, buffering agents, sugars and manganese dioxide as an oxidation catalyst. When the tablets are placed in an aqueous environment, layers of the tablet dissolve over time releasing components therein." At Column 1, lines 7 through 14 DiTuro discloses "This invention is directed to a non-toxic in situ method for the accelerated biological degradation of organic matter in the form of sewage sludge or petroleum hydrocarbons on the surface of aquatic objects submerged in bodies of saltwater, brackish, or freshwater". At col. 3, lines 21-27 DiTuro discloses "This invention proposes an in situ approach to help remediate this problem. Its approach is one in which the ability of naturally occurring and/or seeded microorganisms to break down these contaminants is enhanced by the timed release of oxygen gas, via chemical reaction, and chemical additives such as buffering agents and enzymes."
One disadvantage of the DiTuro system is that the flow of oxygen away from the sludge will create a water current carrying the enzyme away from the sludge.
U.S. Pat. No. 5,543,309 Pischel (Aug. 6, 1996) at the abstract discloses, "A carrier is prepared containing bacteria and/or enzymes for degrading sewage sludge. The carrier can be in the form of a gel containing coloring matter and optionally a deodorant, or in the form of a core for a roll of toilet tissue or roll of towels.--The tube is formed from at least two layers made from cellulose bonded together with a water soluble bonding agent. Enzymes and/or bacteria can be in a slurry of cellulose pulp used to make the core, in the bonding agent, or in a coating or strip on an inside and/or outside layer. The tube contains a plurality of sets of circumferential perforations that enable, after removing the toilet tissue, readily breaking the tube into a plurality of small pieces that can be flushed down a toilet bowl into a sewage system where the pieces disintegrate and release the enzymes and/or bacteria.--"
U.S. Pat. No. 5,089,407 Baker et al (Feb. 18, 1992) discloses at the abstract, "Biological materials such as enzymes. proteins and peptides are encapsulated by forming a mixture of the material and an aqueous non-ionic polymer solution, spraying the mixture into a circulating water-immiscible non-solvent for the polymer at a temperature sufficient to freeze the beads and drying the frozen beads to remove--water--. Suitable non-ionic polymers are poly(vinyl alcohol), polyvinylpyrollidone, dextran and derivatized cellulose. A densification agent--may be present--. Encapsulated material such as microbes produced by this process provide useful agricultural agents --suitable for delivery to soil or plant leaves." At col. 2, lines 1 8-20 Baker et al disclose, "Water soluble non-ionic polymers having a solubility of at least 3% w/v and which are not detrimental to the microbe to be encapsulated can by used."
Except for DeLucia, the bacteria and/or enzymes normally added to a sewage digester tank are added as liquids or solids that immediately dissolve and flow into the digester tank, and many of the bacteria and/or enzymes continue to flow through the digester tank to the discharge without ever coming in contact with the sludge to be digested. DeLucia discloses adding a pellet or a number of pellets having different dissolution rates containing enzymes but no bacteria.